Photographic printing machine



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R. H. DUMKE ET AL PHOTOGRAPHIC PRINTING MACHINE Sept. 6, 1960 FiledSept. 26, 1957 Sept. 6, 1960 R. H. DUMKE ET AL PHOTOGRAPHIC PRINTINGMACHINE Filed Sept. 26, 1957 3 SheetsSheet 2 2 INVENTORS 6w;- H. DUMKESept. 6, 1960 R. H. DUMKE ET AL 2,951,430

PHOTOGRAFHIC PRINTING MACHINE Filed Sept. 26, 1957 3 Sheets-$heet 3 I NVEN TORJ Foeser H. Dum 1 E Evy/"0N0 E. BoDENDOERFER Arrae/vsyf UnitedStates Patent PHOTOGRAPHIC PRINTING MACHINE Robert H. Dnmke and RaymondE. Bodendoerfer, Milwaukee, Wis., assignors to Roloc Incorporated,Milwaukee, Wis., a corporation of Wisconsin Filed Sept. 26, 1957, Ser.No. 686,478

4 Claims. (Cl. 95-76) This invention relates to a photographic printingmachine having a vacuum printing frame and also having sets of coacfingfilters organized for the making of color separation negatives.

The vacuum printing frame is placed at the top of a cabinet which has alight and filters in its lower portion. The transparency and negativematerial are superimposed on the glass of the printing frame and heldthereto by a pressure member which desirably comprises a web of naturalor synthetic rubber having a sponge rubber cushion facing, the web beingconnected at one side to the frame and freely movable to and fromposition over the work. An opening or openings through the glass havevacuum connections so that when the web is placed over the work, all airbetween the cushion and the work and the glass of the frame isimmediately evacuated. Atmospheric pressure on the flexible backing webassures intimate contact between the transparency and the negativematerial (paper or film).

The pressure on the work is accurately controlled by a bleed valve whichcan be adjusted to provide vent relief when the desired degree of vacuumis achieved.

Separation filters, mask filters and neutral density filters are mountedon separate turntables which can be indexed individually to bringselected filters of each turntable into registry with the source ofillumination. -In practice I provide each turntable with four openingsand provide filters for three of these, leaving a clear opening in eachturntable, any one or more of which may be registered between the lampand the work. Control shafts extend downwardly from the level of theprinting frame and have chain and sprocket connections with the variousturntables whereby the position of each may be adjusted by manipulationof its shaft, without affecting the setting of the others.

In the drawings:

Fig. 1 is a view in perspective of apparatus embodying the invention.

Fig. 2 is a view taken through the apparatus of Fig. 1 in verticalsection from front to rear in the plane indicated at 2-2 in Fig. 3.

Fig. 3 is an enlarged detail view taken in section on the line 33 ofFig. 2.

Fig. 4 is a plan view of the apparatus shown in Fig. 2, all controlknobs and dials other than handles for the indexing of the turntablesbeing omitted and the pressure member of the printing frame beingpartially broken away.

Fig. 5 is a view taken in section on the line 5-5 of Fig. 2.

Figs. 6, 7 and 8 are diagrammatic views on a reduced scale showing thevarious turntables in plan, the crosshatching of the filters being forcontrast only.

Fig. 9 is a view taken on an enlarged scale on the line 9-9 of Fig. 4,the vacuum pump and vacuum controlling connections beingdiagrammatically illustrated partially in section and partially in sideelevation.

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The device comprises a cabinet 10 with a front access door 11 clampedshut by means of the cam shaft 12 and sealed by the gasket 13.

At the back of the cabinet is a control panel 15 having a number ofcontrols including a vacuum gauge 16 and a vacuum regulating knob 17,vacuum pump motor switch 113 and exposure timer 111. The remainingcontrols are not pertinent to this particular invention.

The printing frame generically designated by reference character 20comprises a base casting 21 which is downwardly flanged for strength asbest shown in Fig. 9. The glass 22 is supported from this casting on aninterposed gasket 23 and is subject to clamping pressure of the framemember 24 through an upper gasket 25. The screws 26 connect the framemember 24 to the base casting 21.

Suspended from the base casting is a bar 28 from which the locatingdowels 29 project upwardly through openings provided at 30 in the glass22. The work usually comprises a transparency 32 and negative material33. These sheets are punched with holes with which the dowels 29register accurately, whereby the work sheets may be engaged over thedowels and thereby positioned with accuracy on the glass pending closingof the pressure member thereover.

The pressure member generically designated by reference character 35comprises a flexible blanket or web of natural or synthetic rubber at 36which is connected by screws 37 with the frame member 24 whereby theglass is clamped. The web is of suflicient area to extend across theopening in frame member 24. Carried by the web 36 as a part of thepressure member 35 is a flexible sheet of sponge rubber 38 of suchdimensions as to be received within the opening of frame member 24,resting upon the work and upon such portions of the glass 22 as may beexposed outside of the work as shown in Fig. 9. The thickness of thesponge rubber insert 38 will be approximately equal to that of the framemember 24 although this is not critical due to the fact that the entirepressure member 35 is flexible and readily conforms to the work.Openings are provided at 39 in the sponge rubber insert 38 toaccommodate the upper ends of the dowels 29. Desirably the dowels arenot so long as to deflect the web 36, the web being therefore continuousand unbroken over the upper ends of the dowels. The dowels are engagedtightly only by the work, the sockets 39 in the sponge rubber insert 38being suificiently large to afford ample clearance.

The printing frame glass 22 has an opening or openings at 40. I havefound it suflicient to provide two such openings, both located at thefront and near the sides of the opening through the frame member 24. Thevacuum line 42 and branch line 43 provide vacuum connections to theopenings 40 from the vacuum pump 44. Another branch line -45 leads tothe vacuum gauge 16. A bleed line 46 leads from the pressure regulatingvalve generically designated by reference character 50 and shown insection in Fig. 9.

The valve casing 51 has vent ports 52 communicating through a valve seat53 with chamber 54 into which the bleed line 46 opens. The casing has abearing at 55 in which there is carried the stem 56 of spring bias valve57 which is normally engaged with the seat 53.

The valve operated spring 58 is adjustable as to its bias by means of aplug type of spring seat 59 threaded to the casing 51 and provided witha slot 60 of noncircular cross section in which the similarly contouredactuator -61 is engaged. This actuator comprises a feather or key on theend of the spindle 62 which carries the knob 17. A shoulder 63 on thespindle engages the casing interiorly whereby the spindle is anchoredagainst any appreciable axial displacement in the course of itsrotation. In consequence, the knob 17 does not move inwardly oroutwardly but has only rotative movement. The splined connection betweenthe feather or key 61 and the spring seat 59 permits the spring seat tomove inwardly and outwardly upon its threads when rotation is impartedto it by the knob 17.

Whenever the degree of vacuum imposed on the printing frame causes thevalve 57 to be subject to a pressure differential in excess of that towhich its spring 58 is set, the valve opens to admit atmospheric airthrough the vents 52 and past the valve and through the biasing springand through the bleed connection 46 to relieve the vacuum. The reliefcontinues until the spring pressure equals atmospheric pressure on valve57, whereupon the valve closes.

The vacuum pump 44 acts so rapidly that it is practicable to start andstop it when the work is placed and, preliminary to work removal, switch113 being used for this purpose. To predetermine the desired pressure,the operator simply adjusts the knob 17 until the vacuum index is shownon the vacuum gauge 16. This exact degree of vacuum will be maintainedautomatically thereafter whenever the vacuum pump 44 is in operation. Ithas been found that this bleeding arrangement provides much moreaccurate control of the vacuum than is possible in any other manner.

Light for exposing the negative material through the transparency in theprinting frame may be provided from any appropriate source such as thebulb 70 in the base of the cabinet. In practice the chamber 71 in whichthe bulb is located is separated from the rest of the cabinet by ahorizontal partition 72 and upright partition 73. The only opening intothe chamber 74 of the cabinet is through the port 75 immediately abovethe lamp 70 and centered between the lamp and the printing frame.

Mounted within the chamber 74 of the cabinet are the separatelyindexable filter carriers or turntables 80, 81 and 82 mountedrespectively on shafts 83, 84 and 85, the axes of which aresymmetrically disposed about the light-supplying opening 75.

The radii of the various turntables are such that each extends acrossthe opening 75 to intercept light passing from the lamp 70 toward theprinting frame. Each of the turntables is provided with a number ofopenings 86 (four being shown in each) each of which is encircled by acircular flange 87 as best shown in Figs. 3, and 6 to 8. The flanges arespaced from the respective openings to provide shoulders 88 upon whichthe various filters 89 may be placed.

I sometimes superimpose two or more filters, the term filters being usedgenerically herein to include the annuli 90 shown in Fig. 8, which havedifferent sizes of openings and are interchangeably positioned on top ofthe neutral density filters carried by disk 81.

In practice each of the disks is provided with only three filters orsets of filters, one opening being left unobstructed. In the lowest disk81 I mount the neutral density filters, the filters 89 comprisingdifferent shades of gray and the light passing through the filter orfilters being further restricted if desired by the filter annull 90 toany desired extent. On the intermediate disk 80 I employ the maskingfilters 91. On the top disk 82 I provide the color separation filters92. which, as is wellknown in this art, are usually in three colors.

For adjusting the disks or turntables, the shafts 83, 84, 85 areprovided respectively with sprockets 93, 94, 95 driven by chains 96, 97,98 from sprockets 99, 100, 101 on the upright shafts 102, 103 and 104.These shafts extend upwardly through the cabinet and are provided withcontrol handles 105, 106 and 107 respectively. It will be noted that theactuating chains are all olfset from the light projection zone.

In order to assure that the several disks will be scurately fixed in therespective positions to which they are adjusted by these controlhandles, the peripheries of the disks are desirably provided withnotches as shown at 109 in Fig. 5 and in selected positions ofadjustment these notches are engaged by detents 110.

The organization is such that in every operative position of the severalturntables or disks there will be openings 86 of all three disksregistered above the lamp 70 in the direct line between the lamp and theprinting frame. Thus, the selected filters or lack of filters will beelfective in the zone in which the printing frame and the work thereinis irradiated from the source 70. For example, the separation filtersshown in Fig. 6 would almost invariably be used, assuming that theprinter is employed for the making of separation negatives. However, thedisk would normally be adjustable to a position in which its openaperture 86 would be presented to the beam of light. Normally one oranother of the neutral density filters would be placed in the beam andit might also be necessary to use one or another of the masking filtersin conjunction with one of the color separation filters.

The skilled operator will measure his requirements and can almostinstantly adjust the disks to give him the proper color and intensity oflight for the desired printing operation. Using a given transparency, hewill open switch 113 to release the vacuum and will then open theprinting frame following his first exposure, substituting a secondnegative sheet and changing his filter or filters for the secondexposure and repeating for the third color separation negative. Eachtime the flexible blanket or pressure-applying member is replaced overthe work, the vacuum pump will be started by means of the manuallyoperable switch 113. With the work thus firmly clamped against theglass, the lamp or other light source will be energized for a periodpredetermined by the timer 111 to make the exposure through the selectedfilters.

We claim:

1. In a photo-printer, a work-supporting glass, a pressure membermovable to and from work supported on the glass, a vacuum ductcommunicating with the space between the pressure member and the glassfor withdrawing air therefrom, the glass being provided with an aperturecommunicating with said duct and opening into the space between saidpressure member and said glass, means for creating a vacuum in saidduct, a valve for admitting atmospheric air into the duct to relieve thevacuum therein, means biasing said valve against admission ofatmospheric air, means for adjusting the bias on said valve to regulatesub-atmospheric pressure in said duct, a light source for theillumination of said glass from beneath and a plurality of filtercarrier disks having mounting shafts disposed at different sides of saidsource, the respective disks extending across the path of light betweenthe source and the glass and having apertures respectively registrablewith each other upon said path, the disks having filter positioningmeans for disposing filters in respective apertures, and means forrotating the disks to make difierent apertures of respective disksregister with each other on said path, the bleed valve and the means forrotating the filter positioning disks being mounted in proximity to theprinting frame whereby all portions of the device requiring adjustmentby an operator are accessible in one location.

2. In a photo-printer, a cabinet, a printing frame in a horizontalsurface of the cabinet, a light source in the cabinet remote from theframe, a plurality of rotatable shafts spaced on the circumference of acircle about the light source, filter-carrying disks severally supportedon the shafts for overlapping at their intersection with the beam oflight from the source and each having plural apertures registrableseverally with the light source, the disks severally having pluralperipheral notches severally corersponding to the registry of anaperture with the light source, indexing means mounted adjacent eachdisk and engageable in sequence with the notches therein, means forindividually driving the disk supporting shafts for rotation of thedisks to various indexed positions, said means being provided withhandles above said cabinet surface and adjacent the printing frametherein, and comprising shafts severally connected by a chain to asprocket on a disk supporting shaft, the driving shafts being mountedfor aligning the handles along one side of the printing frame.

3. In a photo-printer, the combination with a light source and a remoteprinting frame, of an interposed set of rotatably mounted indexablefilter carriers, each having filter receiving apertures movable with thecarrier across the path of a light beam from the source to the printingframe, the apertures of the several carriers being movable by carrierrotation to and from alignment with selected apetures of anothercarrier, a cabinet supporting the printing frame and enclosing thecarriers and provided with mechanical carrier-adjusting means havinghandles exposed in convenient proximity to the printing frame, the framecomprising a rigidly mounted glass upon which work is receivable and aflexible blanket having a fixed mounting on one side of the glass, anddowel means for fixing the position of work respective the glass, theblanket including a cushion socketed to receive the dowel means and aweb portion to which the cushion is attached and which is continousacross the dowel means, and means for evacuating air from the face ofthe glass in an area covered by the blanket and provided with meansmounted in proximity to the printing frame for manually controlling thedegree of evacuation of air.

4. In a photo-printer, the combination with a light source and remoteprinting frame, of an interposed set of rotatably mounted indexablefilter carriers each having filter-receiving apertures movable with thecarrier across the path of a light beam from the light source to theprinting frame, each of the apertures of the several carriers beingmoved by carrier rotation to and from registry with any selectedaperture of every other carrier, the fame comprising a rigidly mountedglass upon which work is laid and dowel means for fixing the position ofthe work on the glass and a flexible blanket having a fixed mounting atone side of the glass, the blanket including a cushion socketed toreceive the dowel means and a web portion to which the cushion isattached and which is continuous across the dowel means, means" forevacuating air from the face of the glass in an area covered by theblanket whereby the blanket is urged by atmospheric pressure toward theglass, and means ad jacent the printing frame for manually controllingthe degree of evacuation of air.

References Cited in the file of this patent UNITED STATES PATENTS795,470 Anger July 25, 1905 2,420,023 Wekeman May 6, 1947 2,557,182Forgett June 19, 1951 2,625,851 Gelb Ian. 20, .1953 2,672,080 DavidsonMar. 16, 1954 2,721,507 Siok Oct. 25, 1955 2,734,435 Leonardi Feb. 14,1956 2,774,289 Collins Dec. 18, 1956 2,826,976 Gelb Mar. 18, 19582,869,447 Youngberg Ian. 20, 1959

